Method and apparatus for spinning flying fibers into a twisted yarn

ABSTRACT

A twisted yarn is spun by pressing a strand of fibers against a rapidly rotating roller to separate the fibers, pressing the separated fibers against the wall of a main rotary drum, allowing the fibers pressed against the drum wall to be moved in the direction of a fiber condensing portion of the drum, and causing the fibers at this drum portion to be twisted and intertwined with the end of a preceding yarn portion spun in this manner.

Uited States atent Fukuta et al.

[4 1 Sept. 5, 1972 METHOD AND APPARATUS FOR SPINNING FLYING FIBERS INTO A TWISTED YARN Inventors: Kenii Fukuta, Yokohama; Yoshihiro Miura, Yokosuka, both of Japan Assignee: Agency of Industrial Science &

Tec, Tokyo, Japan Filed: June 10, 1970 Appl. No.: 45,153

Foreign Application Priority Data June 11, 1969 Japan ..44/45931 June 11, 1969 Japan ..44/45932 June 25, 1969 Japan ..44/50129 Nov. 17, 1969 Japan ..44/91955 US. Cl. ..57/58.95, 57/589], 57/156 Int. Cl. ..D01h l/12, D01h 7/00 Field of Search ..57/58.89, 58.95, 139, 156

References Cited UNITED STATES PATENTS 12/1969 Shepherd et a1. .....57/58.95 X

3,501,907 3/1970 Tabata et al ..57/139 X 3,511,044 5/1970 Stary ..57/58.95 X 3,355,869 12/1967 Vorisek ..57/58.95 3,620,002 11/1971 Grishin ..57/58.89 3,370,413 2/1968 Rajnoha et a1 ..57/58.95 3,163,976 l/1965 Juillard ..57/58.95 X

FOREIGN PATENTS OR APPLICATIONS 1,170,841 5/1964 Germany ..57/58.95

477,259 12/1937 GreatBritain ..57/58.95

Pn'mary ExaminerDonald E. Watkins AttomeyKurt Kelman [57] ABSTRACT A twisted yarn is spun by pressing a strand of fibers against a rapidly rotating roller to separate the fibers, pressing the separated fibers against the wall of a main rotary drum, allowing the fibers pressed against the drum wall to be moved in the direction of a fiber condensing portion of the drum, and causing the fibers at this drum portion to be twisted and intertwined with the end of a preceding yarn portion spun in this 6 Claims, 11 Drawing Figures PATENTEDsEP 5|972 3.688.487

SHEET 1 0F 4 INVENTORS Puma-A Yo 5H 1 Hike MIKM BY KM KW AGINT PATENTEDSEP 5:912

SHEET '4 0F 4 INVENTOILS KlNII Fu-Kuun (cant-tau mukgq BY KuM: K

Ae-eN-r METHOD AND APPARATUS FOR SPINNING FLYING FIBERS INTO A TWISTED YARN This invention relates to a method and an apparatus for spinning flying fibers into a twisted yarn. More particularly, this invention relates to a so-called drum type open-end spinning method and an apparatus therefor, wherein the production of a spun yarn is accomplished by separating the component fibers of a feed material (such as, for example, a sliver) into individual fibers, leading the separated fibers together with a current of air into a rotary drum and conferring twist upon yarns being assembled on the internal wall of the drum, so that the twisting operation can be effected without involving the rotation of the package (produced yarn wound such as on a cop).

One of the requirements which make feasible the drum type open-end spinning method resides in the fact that the twisting power of the yarn being assembled and subjected to a twisting action on the internal wall of the drum is not transmitted to the bundle of fibers on the feeding side. In the case of a previously proposed openend spinning method, the continuity between the feed material and the spun yarn is broken by allowing fibers of the feed material to fly with a current of air so that the twisting power exerted on the fibers being assembled and twisted may not be transmitted to the feeding side, while fibers of the feed material are successively supplied to the point at which twisting of fibers begins. In this type of spinning method which involves the flying of fibers, fibers in the process of flying assume a free state liberated from all forms of tension except the action which develops because of the velocity gradient of air. Generally, the tension exerted on fibers in flight by the velocity gradient of air (namely, the tension which tends to prevent fibers from being bent) is small. Thus, fibers are bent such as by the resistance ofi'ered thereto while fibers in flight come into contact with the internal wall of a feed tube for guiding flying fibers, with a result that the arrangement of fibers in the resultant yarn tends to be disturbed. Such disturbed arrangement of fibers causes degradation of yarn strength and damages the yarn quality.

In the previously proposed drum type open-end spinning method, fibers in flight are led directly from the outlet of the feed tube to the peripheral plane having the largest diameter throughout the entire internal wall of the rotary drum, namely, the position at which the twisting action is provided (hereinafter referred to as assembling position), with the said outlet pointed fixedly in the direction of the said assembling position.

In methods and apparatus of such principle, the improvement in the degree of orientation of fibers has been devised aerodynamically, such as by increasing the velocity gradient of air inside the feed tube for flying fibers or disposing the fiber outlet of the feed tube close to the assembling plane so as to permit the peripheral velocity of fibers at the assembling position to exceed the flying velocity of fibers and consequently differenciate the travelling velocity of fibers by permitting.

The object of the present invention is to provide a method and an apparatus for spinning flying fibers at a high speed into a yarn having uniform quality.

Other objects and characteristic features of this invention will become apparent from the following description of preferred embodiments of this invention,

particularly if read in conjunction with the accompanying drawing, wherein:

FIG. 1 is a partly sectioned side elevation of an apparatus for separating and flying fibers according to this invention;

FIG. 2 is a top view of the same apparatus;

FIG. 3 is a partly sectioned side elevation of an apparatus for separating and flying fibers in another embodiment of this invention;

FIG. 4 is a top view of the same device;

FIG. 5 is a partly sectioned side elevation of an apparatus for spinning into a twisted yarn those fibers discharged from the apparatus for separating and flying fibers according to the present invention;

FIG. 6 is a cross section along the line VI-VI indicated in FIG. 5;

FIG. 7 is a partly sectioned side elevation of another embodiment of an apparatus for producing a twisted spun yarn;

FIG. 8 is the same embodiment as illustrated above, except the main rotary drum and the rotary element are modified in shape;

FIG. 9 is an explanatory diagram showing the condition in which a fiber moves when the fiber-assembling wall and the auxiliary assembling surface are rotating in the same direction;

FIG. 10 is an explanatory diagram illustrating the condition in which a fiber moves when the fiber-assembling wall and the auxiliary assembling surface are rotating in opposite directions; and

FIG. 11 is a sectional side view of another embodiment of the rotary element.

Referring to FIG. 1 and FIG. 2, a funnel 1 for guiding silver or roving is disposed protrudingly on a, base board 2 and a bottom roller 3 is supported by the base board 2, with a toothed wheel 4 fitted at the end of the axis of the roller 3 so as to receive the rotating motion from a driving source (not illustrated). A top roller 5 is not supported by the base board 2 but is pivotally supported by board 6 having a triangular shape. The board 6 is rotatably supported on the base 2 by the medium of a shaft 7 as illustrated in FIG. 1, so that it can rotate to a position indicated by a dotted line. At the lower end of the board 6, a projection 8 indicated by a dotted line is disposed protrudingly and a weight and a spring are suspended from the projection so as to confer a downward rotating power to the board 6 and, consequently, enable the roller 5 supported thereon to be held in forced contact with the roller 3. An apron band 9 is mounted around the roller 3 and a supporting board 10 which is fixed on the base board 2. Another apron band 11 which is sent around the roller 5 holds on its inner side a tenser 12 which is not fixed to anything in particular. The cooperative action of the supporting board 10 with the pressing power exerted by this tenser l2 enables the two apron bands to be kept in mutually pressed contact on the confronting surfaces thereof. The pressing power of the tenser 12 is supplied from a lever 13. The lever 13 is freely movably supported on the shaft 7 in conjunction with the board 6. A coil spring 14 which is engagedly fitted on this shaft 7 imparts to the lever 13 a rotating power in the clockwise direction around the shaft 7 as shown in FIG. 1. Near the forward end of the lever 13, there is provided a projection 18, which is engaged as illustrated with an engaging member formed on the upper surface of the tenser 12, so that the clockwise rotation of the lever 13 imparts tension to the apron band 11 via the tenser 12 and, further, presses the lower side of the apron band 11 against the upper side of the apron band 9, which in turn is held in position by virtue of the supporting board 10. Thus, the apron bands 11 and 9 have the confronting sides thereof pressed against each other in the vertical direction by means of the tenser 12 and the confronting supporting board 10 and consequently form a section for holding and feeding fibers. In FIG. 2, Numeral 17 denotes a toothed wheel which is fitted inseparably on the roller 5. This toothed wheel 17 is meshed with a toothed wheel 16 fitted at the end of the axis of the roller 3, so that the rotation introduced from the toothed wheel 4 is also transmitted to the roller 5 via the toothed wheels 16 and 17. Accordingly, the roller 3 is driven in conjunction with the roller 5.

In the apparatus of this invention having a construction described above, a sliver or roving fed through the funnel 1 is held between the two apron bands 9 and 1 1 and, with the rotation of the two rollers 3 and 5, forwarded to a fiber-opening roller 20 having needles planted on the surface thereof. The high-speed rotation of the fiber-opening roller serves to separate and fly, which are then supplied via a passage 19 and a pipe 21 into a twisting apparatus.

In the apparatus of FIG. 3 and FIG. 4, a funnel l is disposed protrudingly on a base board 1 and a roller 23 is pivotally supported so as to confront the outlet of the funnel 1. The said roller 23 is rotated by a driving source (not illustrated). A roller is pivotally sup ported on one end of an arm 24 which has the other end thereof vibratably fixed on the base board 2. The said roller 25 is so positioned as to confront the roller 23. A spring 29 is disposed between a spring shoe 26 formed on the arm 24 and a screw 28 helically fitted to an arbor 27 provided on the base board 2. By virtue of this spring 29, the roller 25 is pressed against the roller 23.

A sliver or roving fed through the funnel l is sent between the two rollers 23 and 25 and forwarded to a feed section which comprises four sliding plates 34, 35, 36 and 37 so as to permit a space 38 to occur at the center.

These sliding plates are supported on supporting boards 22 which are fixed on the base board 2. The upper side of these sliding plates is pressed down by two springs 33 fixed on the base board 2 so as to confer on these sliding plates a pressure suitable for fibers to be held in the space 38.

The lower middle portion of each of the four sliding plates is engaged with one end of a corresponding lever 39 which has the other end thereof axially fixed on the base board 2. Four earns 31 are fixed on a rotary shaft in such way as to correspond to the four levers 39. By virtue of four springs 32, these levers are constantly pressed against the corresponding cams 31.

When the rotary shaft 30 is rotated, the earns 31 are rotated so as to vibrate the corresponding levers 39, with a result that the sliding plates engaged with the forward ends of the levers 39 are caused to slide over the supporting boards 22. These earns 31 have their shapes so designed as to produce a quick return motion. To be specific, they are so shaped as to produce a slow motion in the right direction and a quick motion in the left direction respectively. Further, these cams are fixed coaxially on the shaft 30 in such relationship that the identical phases of the cams are skewed regularly by a small angle and, consequently, any three of the four sliding plates are in a slow motion in the right direction and the remaining one sliding plate is in a quick motion in the left direction at any given time. In this case, a sliver or roving which exists inside the space 38 and is pressed against the sliding plates is exposed to the propelling force exerted by the sliding plates in the direction of their travel. Since the combined propelling force exerted by three sliding plates moving in the right direction is greater than that exerted by the remaining one sliding plate moving in the left direction, sliver or roving is fed to the fiber-opening roller 20 having needles planted on the surface thereof. There, the fibers are separated and caused to fly, and flying fibers are forwarded via the passage 19 and pipe 21 into a twisting apparatus.

Separated and flying fibers are converted into a twisted spun yarn by a twisting apparatus like the one illustrated in FIG. 5.

In the apparatus shown in FIG. 5, the internal wall of a funnel-shaped rotary drum 40 which is provided at one end with an opening for receiving a pipe 21 adapted to feed flying fibers comprises a fiber-assembling wall 42, a fiber condence portion 43 located the point of the largest diameter, a twisting wall 44 having a cross-section gradually reduced in diameter in the direction from the fiber-assembling wall 43 to the nozzle 41, and an air discharge wall 45 having a cross section gradually reduced in diameter in the direction from the fiber-assembling wall 42.

The other end of the said drum 40 is connected to the nozzle 41 which has the outer periphery thereof supported by the bearings 46. The rotation produced by a motor (not illustrated) is transmitted to a pulley 4'7 fixed on the outer periphery of the nozzle 41, causing the nozzle to be rotated at a high speed.

While in the process of flight along the current of air being discharged as indicated by the arrow mark in a direction opposite the direction of the flight of fibers inside the pipe 21, flying fibers led via the pipe 21 to the rotary drum 40 are pressed against the fiber-assembling wall 42 by the helical current of air produced by the high-speed rotation of the fiberassembling wall 42 and the centrifugal force exerted on fibers themselves. The fibers which are now pressed against the fiber-assembling wall 42 are caused to move in the direction of the fiber condensing portion 43 while being pressed against the fiber-assembling wall 42 by virtue of the centrifugal force resulting from the rotation of the drum, the component of force exerted along the fiberassembling wall 42 and the component of force produced in a direction perpendicular to the fiber-assembling wall 42. While the fibers are in the process of moving from the fiber-assembling wall 42 to the fiber condensing position 43 as illustrated in FIG. 6, they are subjected to a tension developed in consequence of the increase in the diameter of the peripheral wall and, as a result, the fibers assume a straight state (namely, a state free from bending or zigzagging) along the peripheral wall. Thus is heightened the degree of orientation of fibers in their assembled state at the fiber condensing portion 43. Further, since the air inside the rotary drum 41 is discharged along the fiber-assembling wall 42, flying fibers are not allowed to interwine directly with the portion of yarn being formed on the twisting wall 44. Thus, the spun yarn is prevented from nap formation (jamping fibers). FIG. 6 illustrates a condition in which one fiber reaches the fiber condensing position 43. When fibers are continuously collected on the fiber-assembling wall 42, however, they form an annular layer of fibers along the peripheral wall of the fiber-assembling wall and reach the fiber condence portion 43 while being subjected to a concentrical drafting action. These fibers are assembled up to such number as is required for the construction of a yarn, converted into a yarn 48 by the twisting action exerted thereon and then discharged through the nozzle 41 in the form of a yarn.

The angle to be formed between the fiber-assembling wall 42 and the plane perpendicular to the axis of rotation thereof is determined in such way as to produce effective improvements in the movement of fibers to the fiber condensing position as well as in the orientation of fibers clue to the annular drafting motion. In addition, the length of the pipe 22 inside the drum and the angle formed between the pipe and the fiber-assembling wall are suitably fixed at such values as to ensure effective collection of flying fibers on the fiber-assembling wall. In FIG. 5, the direction in which the air inside the rotary drum is discharged is clearly indicated to be opposite the direction of the flight of fibers inside the feed pipe 21.

So far as no hindrance is placed to the satisfactory function of auxiliary fiber assembling, however, this direction need not be totally opposite the direction of the flight of fibers inside the feed pipe.

In FIG. 7 and FIG. 8, the internal wall of the funnelshaped main rotary drum 49 which is provided at one end with an opening for inserting a rotary element 50 comprises a fiber-assembling wall 51 for collecting flying fibers, a fiber condensing portion 52 located at the point of the largest diameter, and a twisting wall 53. The rotary element 50 is supported by the panel 55 inseparably fixed on the bearing in such way that the auxiliary twisting surface 50 of the rotary element 50 confronts the twisting wall 53 of the rotary drum 49, so that it rotates at a high speed in the same direction as, or in the opposite direction to, that of the rotary drum 49. A space 54 is inserted between the panel 55 and the opening of the rotary drum 49 to permit discharge of the air introduced into the rotary drum 49. On the panel 55, holes 58 for leading flying fibers into the rotary drum 49 is disposed so as to point to the auxiliary fiber-assembling surface 57 of the rotary element 50.

The twisting wall 53 of the main rotary drum 49 may be so disposed as to form an acute angle with the axis of rotation as illustrated in FIG. 7 or to form an obtuse angle as illustrated in FIG. 8. Further, the auxiliary fiber-assembling surface 57 of the rotary element 50 may have an acute-angled shape as shown in FIG. 7 or an obtuse-angled shape as shown in FIG. 8.

The flying fibers which have been conveyed in the current of air through the pipe 22 flow out of the holes 58 in the direction of the auxiliary fiber-assembling surface 57 of the rotary element 50 and, by virtue of the current of air being discharged outwardly from within the rotary drum 49, pressed against the auxiliary fiberassembling surface 57. When the rotating speed of the auxiliary fiber-assembling surface 57 is greater than the flying speed of fibers at the time the fibers are pressed against the auxiliary fiber-assembling surface, a tension is exerted on such fibers and, consequently, the fibers are pressed, without being bent, against the said surface.

The fibers which are now pressed against the said surface 57 are made to move toward the rim of the said surface 57 by the centrifugal force produced by the surface 57 rotating at a high speed and the action of the current of air consequently produced nearby. The fibers which exist on the auxiliary fiber-assembling surface 57 are caused by the centrifugal force to move successively toward the fiber-assembling wall 51 of the main rotary drum 49.

Where both the auxiliary fiber-assembling surface 57 and the fiber-assembling wall 51 rotate in the same direction as shown in FIG. 9 and the rotating speed of the fiber-assembling wall 51 is greater than that of the auxiliary fiber-assembling surface 57, the fibers are tensed by virtue of the tension which develops as they move toward the periphery of the auxiliary fiber-assembling surface 57. As they further move on from the auxiliary fiber-assembling surface 57 to the fiber-assembling wall 51, the difference in rotating speed between the surface 57 and wall 51 adds to the tension of fibers, causing the fibers to be arranged in one same direction. FIG. 10 represents a case in which the auxiliary fiberassembling surface 57 and the fiber-assembling wall 51 are rotating in opposite directions. The fibers which have moved to the rim of the auxiliary fiber-assembling surface 57 are reversed at the time they move to the fiber-assembling wall 51. The rotating speeds of the surface 57 and wall 51 must be so adjusted that, the tension exerted on the fibers reaches the maximum magnitude at the time of such movement of fibers.

On reaching the fiber-assembling wall 51, the fibers are assembled by the centrifugal force onto the fiber condence portion 52 which corresponds to the point of the largest diameter of the main rotary drum 49 and thence forwarded successively, while being subjected to a twisting action, to the point at which they are interwined with the beginning portion of a yarn 48 being formed. Then, they are discharged in the form of a yarn through the nozzle 59 of the main rotary drum 49 or the nozzle 60 of the rotary element 50.

No matter whether the yarn 48 is withdrawn in the direction of the nozzle 59 provided on the main rotary drum 49 or in the direction of the nozzle 60 fitted on the rotary element 50, the number of twists in the spun yarn is substantially determined by the spinning length of yarn per unit time and the rotation number of the main rotary dram. Since the rotation of the rotary element can be fixed without reference to the number of twists of the yarn and the spinning speed, possible friction produced at the surfaces where the yarn comes into contact with various parts of the rotary element can be reduced and the propagation of the twisting motion from the nozzle portion to the fiber condence portion can be improved by setting the relative rotations of the yarn and the various parts of the rotary element at suitable magnitudes.

When the yarn 48 is withdrawn through the nozzle 59 of the main rotary drum 49, the free end of the preceding yarn rotates between the twisting wall 53 and the fiber condensing portion 52 and the fibers which have moved to the fiber condensing portion 52 are successively intertwined with that free end of the yarn. The twist of the yarn is winded by the drawing roller for the spun yarn (not illustrated). If the contact resistance issued between the yarn and the nozzle is strong, it 1 becomes difficult for the twisting motion to be propagated to the free end of the yarn. For the purpose of enhancing the propagation of the twisting motion occurring at the fiber condensing portion and the twisting wall and ensuring accurate twisting and intertwining of the yarn, therefore, it is necessary to decrease sufficiently the angle of the twisting wall of the rotary drum with reference to the axis of rotation, reduce possible resistance developing at the bent portion of the nozzle and increase the propagation of the twisting motion.

Where the yarn 48 is withdrawn through the nozzle 60 of the rotary element 50, no matter whether the rotary drum 49 and the rotary element 50 are rotated in one same direction or in opposite directions, a suitable magnitude of tension is produced during the withdrawal of the yarn and an accurate motion is produced at the free end of the rotating yarn. Consequently, there can be produced a spun yarn with stable twists. When a spun yarn is produced by rotating the main rotary drum and the rotary element in opposite directions to each other, the force which tends to reverse the yarn by virtue of contact at the nozzle inlet of the rotary element 50 acts in such way as to impart false twist to the twisted yarn produced inside the nozzle 60 in the free end of yarn. Consequently, there is brought about an improvement in the effect of propagation of the twisting motion to the fiber condensing portion and; at the same time, it becomes possible to produce a yarn having a very small number of twists.

Further, radial holes 61 are, as shown in FIG. 11, provided in the rotary element 50. Air is jetted from the rim of the largest diameter of the said element thereby preventing flying fibers from directly jumping to the yarn at the twisting wall 53 and further preventing fibers from floating from the inner wall of the main rotary drum because of the oscillation, etc. in cases where the main rotary drum rotates at a high speed.

The present invention has made it possible to produce a spun yarn of uniform quality because flying fibers are temporarily pressed against the inner wall of the rotary drum and thence spun into a twisted yarn subsequent to being adjusted in the arrangement of individual fibers as described above.

When a rotary element is provided rotatably between the feeding side of flying fibers and the yarn spinning side, flying fibers can be prevented from intertwining into the yarn being spun.

Furthermore, since the apparatus for separating and flying fibers according to the present invention has a long soft nip element, long fibers can be easily separated and supplied to the twisting apparatus uniformly.

We claim:

1. A method for producing a twisted spun yarn from flying fibers, which comprises the steps of:

A. pressing a strand of fibers against a fiber-opening roller rotating at a high speed; i

B. separating and flying fibers at Step (A);

C. introducing said flying fibers centrally into a rotating drum having a fiber condensing portion at the point of largest inner diameter formed by a fiberassembling wall and a fiber-twisting wall;

D. passing flying fibers after introducing (C) against said fiber-assembling wall and in the direction of fiber condensing portion of said rotating drum;

E. twisting the fibers along the fiber-twisting wall into yarn; and

F. removing yarn being spun.

2. A method for producing a twisted spun yarn from flying fibers, which comprises the steps of:

A. pressing a strand of fibers against a fiber-opening roller rotating at a high speed;

B. separating and flying fibers at Step (A);

C. introducing said flying fibers centrally into a rotating drum and against a rotating auxiliary fiber-assembling surface;

D. passing said fibers from Step (C) to a rotating drum having a fiber condensing portion at the point of largest inner diameter formed by a fiberassembling wall and a fiber-twisting wall, said fibers being passed against the fiber-assembling wall by means of a current of air and centrifugal force;

E. causing the fibers to be moved from the fiber-assembling wall and in the direction of the fiber condensing portion of said rotating drum;

F. twisting the fibers along the fiber-twisting wall into yarn; and

G. removing yarn being spun.

3. A method for producing a twisted spun yarn from flying fibers, which comprise the steps of:

A. pressing a strand of fibers against a fiber-opening roll rotating at a high speed;

B. separating and flying fibers at Step (A);

C. introducing said flying fibers centrally into a rotating drum and against a rotating auxiliary fiber-assembling surface having a funnel-shaped portion with a fiber-assembling surface disposed within a rotating main rotary drum, said drum having a fiber condensing portion at the point of largest inner diameter formed by a fiber-assembling wall and a second wall disposed at an obtuse angle with the axis of drum rotation, said drum rotating at a high speed and in a direction opposite that of said assembling surface;

D. passing said flying fibers from Step (C) against fiber-assembling wall by means of a current. of air and centrifugal force;

E. causing the fibers to be moved from the fiber-assembling wall and in the direction of the fiber condensing portion of said rotating drum;

F. moving the fibers from the said condensing por tion to the fiber-assembling area of the auxiliary surface;

G. twisting the fibers along the fiber-twisting wall into yarn; and

H. removing yarn being spun.

4. An apparatus for producing a twisted spun yarn from flying fibers, comprising in combination: a fiberopening roller having needles planted on the surface thereof, a main rotary drum providing internally a fiber condensing portion at the point of largest inner diameter formed by a fiber-assembling wall, and a fiber twisting wall, and a rotary element disposed inside said rotary drum and possessed of an auxiliary fiber-assembling surface and an auxiliary twisting surface, whereby fibers may be separated and flown by the fiber-opening roller and then pressed against the auxiliary fiber-assembling wall of the rotary element, the fibers which are now in the pressed condition being caused to move to the fiber-assembling wall of the rotary drum and then, onto the fiber condensing portion and the twisting wall, where fibers are twisted and intertwined with the 

1. A method for producing a twisted spun yarn from flying fibers, which comprises the steps of: A. pressing a strand of fibers against a fiber-opening roller rotating at a high speed; B. separating and flying fibers at Step (A); C. introducing said flying fibers centrally into a rotating drum having a fiber condensing portion at the point of largest inner diameter formed by a fiber-assembling wall and a fiber-twisting wall; D. passing flying fibers after introducing (C) against said fiber-assembling wall and in the direction of fiber condensing portion of said rotating drum; E. twisting the fibers along the fiber-twisting wall into yarn; and F. removing yarn being spun.
 2. A method for producing a twisted spun yarn from flying fibers, which comprises the steps of: A. pressing a strand of fibers against a fiber-opening roller rotating at a high speed; B. separating and flying fibers at Step (A); C. introducing said flying fibers centrally into a rotating drum and against a rotating auxiliary fiber-assembling surface; D. passing said fibers from Step (C) to a rotating drum having a fiber condensing portion at the point of largest inner diameter formed by a fiber-assembling wall and a fiber-twisting wall, said fibers being passed against the fiber-assembling wall by means of a current of air and centrifugal force; E. causing the fibers to be moved from the fiber-assembling wall and in the direction of the fiber condensing portion of said rotating drum; F. twisting the fibers along the fiber-twisting wall into yarn; and G. removing yarn being spun.
 3. A method for producing a twisted spun yarn from flying fibers, which comprise the steps of: A. pressing a strand of fibers against a fiber-opening roll rotating at a high speed; B. separating and flying fibers at Step (A); C. introducing said flying fibers centrally into a rotating drum and against a rotating auxiliary fiber-assembling surface having a funnel-shaped portion with a fiber-assembling surface disposed within a rotating main rotary drum, said drum having a fiber condensing portion at the point of largest inner diameter formed by a fiber-assembling wall and a second wall disposed at an obtuse angle with the axis of drum rotation, said drum rotating at a high speed and in a direction opposite that of said assembling surface; D. passing said flying fibers from Step (C) against fiber-assembling wall by means of a current of air and centrifugal force; E. causing the fibers to be moved from the fiber-assembling wall and in the direction of the fiber condensing portion of said rotating drum; F. moving the fibers from the said condensing portion to the fiber-assembling area of the auxiliary surface; G. twisting the fibers along the fiber-twisting wall into yarn; and H. removing yarn being spun.
 4. An apparatus for producing a twisted spun yarn from flying fibers, comprising in combination: a fiber-opening roller having needles planted on the surface thereof, a main rotary drum providing internally a fiber condensing portioN at the point of largest inner diameter formed by a fiber-assembling wall, and a fiber twisting wall, and a rotary element disposed inside said rotary drum and possessed of an auxiliary fiber-assembling surface and an auxiliary twisting surface, whereby fibers may be separated and flown by the fiber-opening roller and then pressed against the auxiliary fiber-assembling wall of the rotary element, the fibers which are now in the pressed condition being caused to move to the fiber-assembling wall of the rotary drum and then, onto the fiber condensing portion and the twisting wall, where fibers are twisted and intertwined with the end of the preceding yarn being spun.
 5. The apparatus according to claim 4 wherein the means for supplying fibers to the fiber-opening roller comprises a hold-and-feed member having two opposed apron bands disposed in mutual contact.
 6. The apparatus according to claim 4 wherein the means for supplying fibers to the fiber-opening roller comprises a hold-and-feed member having a plurality of sliding plates adapted to slide in mutual contact, the said sliding plates being designed to produce independent reciprocating motions. 